Congress will take action on immigration, energy, entitlement reform, and ethics; AND,

The American people will view those challenges as 'solved' in a meaningful way.

Unless things change dramatically in 16 months, the American electorate will be awfully restive come election day. They are likely to want significant change in Washington.

Now consider the candidates. Who's best situated to take advantage of that?

OUTSIDERS:

Michael Bloomberg: Bloomberg fits the bill. While a lifelong liberal, he hasn't been a (registered) Democrat in a while. He governed a Democratic city as a nominal Republican. He is seen as having solved big problems and gotten Republicans and Democrats to work together. He'll run as an Independent. Credentials on 'independence' and 'change?' Best in the field.

Barack Obama: As an African-American, he clearly is somewhat different. Plus, his style and manner seem a 'breath of fresh air.' He'd be more credible than some in talking about 'changing the tone' in Washington. Still, his record on the issues is that of an old-line Kennedy liberal. The GOP nominee would have fun contrasting the rhetoric and the substance.

Rudy Giuliani: Not shockingly, his profile is similar to Bloomberg's. His record is that of a problem solver (crime, budget, welfare, and the economy in NYC) who can bring Republicans and Democrats together. His high-profile unwillingness to shift on abortion enhances his credibility. The only knock on his outsider status is that he actually has been a defender of the Bush administration.

Fred Thompson: Outsider credentials? He's an actor; he served just one full Senate term and then showed no desire to return to elective office; and he sounds like the no-nonsense, maverick outsider (a persona that's heavily reinforced in his acting roles). Weaknesses? He will be painted as a DC lawyer/lobbyist, and there's more than some truth to the characterization. Can he promise to get Republicans and Democrats to work together? Perhaps not -- but he will probably strive to be the fed-up outsider who promises to shake things up -- and he might be the strongest in the field in that respect.

MIXED RECORD:

John Edwards: He hasn't served in office for several years, and his 'two Americas' message has a strong and inherent outsider flavor. His criticisms of Democrats in DC help him as well. Undercutting the outsider image is that he's been running for President since 2003 or so.

John McCain: Has spent a lifetime in Washington, fighting the establishment. Outsider credentials? Mixed. Bipartisan credentials are excellent, due to McCain-Feingold and McCain-Kennedy. Those bipartisan credits also seem likely to prove fatal to his candidacy.

Mitt Romney: Pretty good outsider/change credentials. He is not of Washington; he solved problems in Massachusetts (health care), and he certainly worked with Democrats -- plus he's the closest thing to an 'Iraq critic' now in the GOP field. His achilles heel is the perception that he has dramatically changed position to get in line with GOP orthodoxy.

THE INSTITUTION:

Hillary Clinton: Outsider credentials? She's a woman. That counts for something, but apart from that she's the closest thing to a Washington institution in this race. Can she promise to 'change the tone,' or 'get Republicans and Democrats to work together?' Not a chance in hell. Plus, after 20 straight years of Bushes and Clintons, she's the only one in the field that offers more of the same. If she wins the nomination and the electorate wants change, she could get trounced in the general election -- particularly if Bloomberg runs.

Am I missing anything? It seems to me that if voters want change in DC -- and they will -- then the candidates best positioned to take advantage are Bloomberg, Obama, Giuliani and Thompson. This doesn't mean of course, that these are the best candidates overall -- they all have plenty of other strengths and weaknesses. But in a general election, 'outsider/change' credentials are likely to be a big boost.